There are many different prior-art elevator safety devices that can be used to create a temporary safety space in an end portion of an elevator shaft. The commonest arrangement for accomplishing this is to use mechanical stop blocks arranged to stop the elevator car and prevent it from reaching the extremity of the elevator shaft. A proposed solution for implementing this is to use e.g. a mechanical stop block attached to the elevator shaft and arranged to be moved into the path of a mechanical stop block attached to the elevator car. There are also arrangements for providing a safe space for a serviceman above an elevator car where a stopper attached to the elevator car can be activated by the serviceman by temporarily moving the stopper into a position such that the stopper is set in alignment with a stopper provided in the elevator shaft. In the above-described solutions, the elevator car can only move until the mutually aligned stoppers meet, whereafter the elevator car is unable to move further. In this way, elevator car movement can be restricted for the time during which a serviceman is working e.g. on the top of the elevator car. Otherwise the serviceman would be exposed to the risk of being caught between the elevator car and the end of the elevator shaft. Prior-art technology is described in patent specifications EP1473264, EP1604934, EP1674416A1 and FR2795060A1, among others.
The problems encountered in prior-art solutions include the facts that each stopper has to be activated separately, the stoppers are difficult to activate from a landing door without stepping onto the top of the elevator car, the solutions are complicated and take up plenty of space, a separate limit switch must be provided for each movable stopper and the safety devices are slow and unsafe to activate.